Article
Computer Science, Interdisciplinary Applications
Ashesh Sharma, Shreyas Ananthan, Jayanarayanan Sitaraman, Stephen Thomas, Michael A. Sprague
Summary: This study investigates the use of overset meshes in predicting accurate wind farm aerodynamics involving large motions and complex geometry components. The study examines the influence of information exchange and compares different approaches for coupling overlapping meshes. Experimental results show that linear interpolation and few outer iterations are sufficient for achieving asymptotic convergence of engineering quantities of interest in incompressible flow simulations.
JOURNAL OF COMPUTATIONAL PHYSICS
(2021)
Article
Thermodynamics
Diego Alcaniz, Paolo Caccavale, Maria Valeria De Bonis, Ruth de los Reyes, Maria Dolores Ortola, Gianpaolo Ruocco
Summary: A new fluid heater based on BCET was proposed in this paper, with fully-dimensional thermo-fluid analysis implemented to achieve more uniform and effective heat transfer to temperature-sensitive working fluids. Through geometry optimization with internal baffles, the uncontrolled temperature excess was significantly reduced, while the pressure drop across the flow device was also lowered.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Physics, Multidisciplinary
Dario Amirante, Vlad Ganine, Nicholas J. Hills, Paolo Adami
Summary: This paper presents a coupling framework for parallel execution of different solvers for multi-physics and multi-domain simulations. The coupling architecture is based on multiple instances of the same coupling code and uses independent servers for data exchange. The strategy is considered accurate and efficient for turbomachinery applications involving Conjugate Heat Transfer analysis and Sliding Plane interfaces.
Article
Multidisciplinary Sciences
Dijia Zhang, Longlong Gao, Shaoliang Zhou, Yuxuan Ma, Baoren Li
Summary: This paper proposes a new measurement method for the mass-flow-rate characterization parameters of high-pressure pneumatic servo valves (HPSVs) based on the principle of the series connection sonic discharge of valve orifices. The accuracy of the measured effective cross-sectional area and critical pressure ratio of the HPSV was high, and the findings have general implications for the accurate design, analysis, and control of high-pressure pneumatic servo systems.
SCIENTIFIC REPORTS
(2022)
Article
Chemistry, Analytical
Maciej Szudarek, Mateusz Turkowski, Adam Piechna
Summary: In this study, a numerical model of a mechanical oscillator flowmeter was developed and validated against experimental data. The influence of various factors such as turbulence model, dynamic mesh method, and grid and time step size was investigated. The model exhibited correct qualitative behavior and can be used to study flowmeter operation in detail and improve its performance.
Article
Thermodynamics
Jianqing Wang, Tianqi Liu, Chaozhong Xu, Jiajun Wang, Lian-Fang Feng
Summary: Computational fluid dynamics was used to study the laminar hydrodynamics and heat transfer characteristics of highly viscous fluid in a Sulzer mixer reactor (SMR), which showed better performance in terms of mixing and heat transfer compared to a straight tube heat exchanger (STHE) and a straight tube heat exchanger with segmental baffles (STHE-SG). SMR exhibited more uniform velocity and temperature distributions, as well as a narrower residence time distribution. The regularly arranged heat exchange tubes in SMR helped to continuously twist and split the highly viscous fluid, leading to radial mixing and improved heat transfer efficiency.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Computer Science, Interdisciplinary Applications
Hao Fu, Jian Xia, Shuling Tian
Summary: In this paper, a new OGA strategy is proposed for the re-assembly process in dynamic grid systems. It defines a new set of cells based on the recognition and expansion process of the hole boundary, leading to an acceleration in assembly and wall distance calculation. The proposed method also improves static OGA without the need for additional mesh and only minor program changes. Experimental results show a 50% reduction in time consumption compared to the original method, particularly in the improvement of wall distance calculation. (c) 2023 International Association for Mathematics and Computers in Simulation (IMACS). Published by Elsevier B.V. All rights reserved.
MATHEMATICS AND COMPUTERS IN SIMULATION
(2023)
Review
Thermodynamics
Xiaofeng Yang, Guangming Xiao, Yanxia Du, Lei Liu, Dong Wei, Yewei Gui
Summary: This article summarizes the relationship between heat transfer phenomena and interface effects in high-enthalpy and high-speed flow, emphasizing the importance of modeling and simulating these phenomena in ensuring thermal safety of high-speed flight, and discusses recent research activities at the China Aerodynamics Research and Development Center in this field.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
R. Siddharth, Shaik Subhani, Rajendran Senthil Kumar
Summary: The study investigates the flow and heat transfer characteristics of two hot circular bodies in a 2D simulation. By optimizing the geometry, maximum heat dissipation can be achieved. The positioning of the cylinders in the enclosure has a significant impact on heat transfer rate.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
Article
Energy & Fuels
Ryno Laubscher, Pieter Rousseau
Summary: This study introduces a refined particle diameter-dependent emissivity and scattering factor model for computational fluid dynamics modelling of heat exchangers in boilers firing high ash fuels. The results indicate that the new model predicts lower radiation emission compared to existing models, primarily due to reduced particle emission resulting from the particle diameter-emissivity relationship. Additionally, good agreement was found between calculated and measured steam temperatures in real plant measurements.
Article
Thermodynamics
Inderjot Kaur, Roop L. Mahajan, Prashant Singh
Summary: This paper presents a numerical study on the effective thermal conductivity of architectured materials manufactured by additive manufacturing. The study simulated different unit cell topologies, porosity values, and thermal conductivities to establish a correlation for the effective thermal conductivity. The proposed correlation is applicable to various unit cell topologies and can predict the thermal conductivity of high-porosity metal foams with accuracy.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
D. Sanchez, J. A. Almendros-Ibanez, A. Molina, F. Bozzoli, L. Cattani, J. I. Corcoles
Summary: This study presents the results of a numerical simulation on the heat transfer performance of Newtonian and non-Newtonian fluids in a helical coiled tube under laminar regime. The rheological properties of the non-Newtonian fluids significantly influence the heat transfer rate, with higher heat transfer occurring in the helical section compared to the straight section. Furthermore, the mixing of the non-Newtonian fluids is improved in the coil section, leading to enhanced heat transfer.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Physics, Condensed Matter
Abdelkader Souigat, Zineb Korichi, Dris Slimani, Yamina Benkrima, Mohammed Tayeb Meftah
Summary: In this study, the fractional derivative orders were found to have a significant impact on the diffusion behavior and depth characteristics of the p-n junction in a semi-infinite medium. Increasing the order of the time-fractional derivative resulted in faster diffusion and deeper p-n junctions, while increasing the order of the space fractional derivative led to slower diffusion and shallower p-n junctions.
EUROPEAN PHYSICAL JOURNAL B
(2023)
Article
Engineering, Mechanical
Simone Paccati, Lorenzo Mazzei, Antonio Andreini, Bruno Facchini
Summary: Effusion cooling is an important technology for liner cooling in modern combustion chambers. Due to the high computational cost, simplified CFD approaches and machine learning techniques can be used to accurately predict velocity profiles and temperature distributions with reduced computational cost.
JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME
(2022)
Article
Engineering, Mechanical
Victor Roda-Casanova, Francisco Sanchez-Marin, Raul Martinez-Cuenca
Summary: Heat convection is a significant factor in the cooling process of polymer spur gears running in dry conditions, affecting the gear strength. A numerical heat convection model is proposed in this study, based on a detailed CFD simulation, to investigate heat convection on the external surfaces of the gears. Parametric studies reveal that the relative differences between the results obtained from this model and a representative classical heat convection model can reach up to 125% in terms of heat transfer coefficients. An optimized heat convection model, using empirical equations derived from Newton's law of cooling, is proposed to improve the accuracy of the classical models while reducing the maximum relative differences to 10%.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Nuclear Science & Technology
Ketan Mittal, Ahti Suo-Anttila, Miles Greiner
NUCLEAR TECHNOLOGY
(2015)
Article
Mathematics, Applied
Ketan Mittal, Paul Fischer
JOURNAL OF SCIENTIFIC COMPUTING
(2019)
Article
Mathematics, Applied
Veselin Dobrev, Patrick Knup, Tzanio Kolev, Ketan Mittal, Vladimir Tomov
SIAM JOURNAL ON SCIENTIFIC COMPUTING
(2019)
Article
Computer Science, Interdisciplinary Applications
Veselin Dobrev, Patrick Knupp, Tzanio Kolev, Ketan Mittal, Robert Rieben, Vladimir Tomov
COMPUTERS & FLUIDS
(2020)
Article
Computer Science, Interdisciplinary Applications
Ketan Mittal, Som Dutta, Paul Fischer
COMPUTERS & FLUIDS
(2020)
Article
Mechanics
Alexandre Fabregat, Ferran Gisbert, Anton Vernet, Som Dutta, Ketan Mittal, Jordi Pallares
Summary: This study numerically investigates the hydrodynamics produced by a violent expiratory event resembling a mild cough, showing that factors like exhaled velocity, buoyancy, and temperature differences affect gas dispersion dynamics. Numerical results suggest that while analytical models provide reasonable estimates of the distance traveled by the gas puff, trajectory predictions show larger deviations from the direct numerical simulation (DNS).
Article
Computer Science, Interdisciplinary Applications
Veselin Dobrev, Patrick Knupp, Tzanio Kolev, Ketan Mittal, Vladimir Tomov
Summary: The study introduces an hr-adaptivity framework for optimization of high-order meshes, extending the r-adaptivity method with nonconforming adaptive mesh refinement to better satisfy geometric targets. The methodology is purely algebraic, applicable to various types of meshes and dimensions, and achieves similar accuracy results with significantly fewer mesh nodes.
ENGINEERING WITH COMPUTERS
(2022)
Article
Mechanics
Alexandre Fabregat, Ferran Gisbert, Anton Vernet, Josep Anton Ferre, Ketan Mittal, Som Dutta, Jordi Pallares
Summary: Airborne particles play a significant role in the transmission of COVID-19 and other infectious diseases, particularly when individuals talk, sing, cough, or sneeze. The dynamics of particles dispersed in the air evolve differently based on their sizes, with specific aerosol diameters showing increased residence time and horizontal range under typical ambient conditions.
Article
Computer Science, Interdisciplinary Applications
Ketan Mittal, Som Dutta, Paul Fischer
Summary: The study introduces a multirate timestepper for semi-implicit solutions of the unsteady incompressible Navier-Stokes equations, based on a multidomain spectral element method. The novelty lies in the development of a stable overlapping Schwarz method directly applied to the Navier-Stokes equations, rather than to the convective, viscous, and pressure substeps commonly used in most solvers.
JOURNAL OF COMPUTATIONAL PHYSICS
(2021)
Article
Mechanics
Pallav Ranjan, Ketan Mittal, Leonardo P. Chamorro, Rafael O. Tinoco
Summary: High-resolution large eddy simulations and laboratory experiments were used to evaluate the flow response to gaps in cylinder arrays. The results showed that the gaps affected the flow statistics in the upstream and downstream regions of the canopy, and the in-plane turbulent kinetic energy exhibited a consistent decay rate. The emergent canopy acted as a passive turbulence generator for the gap flow.
Article
Multidisciplinary Sciences
C. J. Lloyd, K. Mittal, S. Dutta, R. M. Dorrell, J. Peakall, G. M. Keevil, A. D. Burns
Summary: This study investigates the flow over smooth denticles on shark skin in an open-channel flow. It is found that there are large pressure peaks and viscous drag at the edges of the denticles. Although the denticles produce lift forces and positive spanwise torques, they ultimately increase the drag by 58% compared to a flat plate. RANS models provide good predictions of drag distributions, although they underestimate the turbulent kinetic energy production and subsequently the drag.
ROYAL SOCIETY OPEN SCIENCE
(2023)
Article
Computer Science, Software Engineering
Jorge-Luis Barrera, Tzanio Kolev, Ketan Mittal, Vladimir Tomov
Summary: We propose a method for morphing high-order meshes to align with implicitly defined geometries. The method formulates the mesh optimization problem using a variational minimization approach and a penalty term. It utilizes a source mesh to represent the level set function accurately and incorporates adaptive strategies for setting the penalization weight and selecting the faces of the mesh to fit the target isocontour. The proposed method is demonstrated to be robust for generating boundary-and interface-fitted meshes for curvilinear domains.
COMPUTER-AIDED DESIGN
(2023)
Proceedings Paper
Engineering, Mechanical
Ketan Mittal, Miles Greiner
PROCEEDINGS OF THE ASME PRESSURE VESSELS AND PIPING CONFERENCE, PVP 2012, VOL 7: OPERATIONS, APPLICATIONS AND COMPONENTS
(2012)
Article
Computer Science, Interdisciplinary Applications
Jin Bao, Zhaoli Guo
Summary: At the equilibrium state of a two-phase fluid system, the chemical potential is constant and the velocity is zero. However, it is challenging to capture this equilibrium state accurately in numerical simulations, resulting in inconsistent thermodynamic interfacial properties and spurious velocities. Therefore, numerical schemes with well-balanced properties are preferred for simulating two-phase flows.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Brian C. Vermeire
Summary: This study presents a framework for implicit large eddy simulation (ILES) of incompressible flows by combining the entropically damped artificial compressibility (EDAC) method with the flux reconstruction (FR) approach. Experimental results demonstrate that the method is accurate and stable for low-order solutions, while higher-order solutions exhibit significantly higher accuracy and lower divergence error compared to reference direct numerical simulation.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Mijian Li, Rui Wang, Xinyu Guo, Xinyu Liu, Lianzhou Wang
Summary: In this study, the flow mechanisms around wall-mounted structures were investigated using Large Eddy Simulation (LES). The impact of inflow turbulence on the flow physics, dynamic response, and hydrodynamic performance was explored. The results revealed strong interference between velocity fluctuations and the wake past the cylinder, as well as significant convection effects in the far wake region.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Donatella Passiatore, Luca Sciacovelli, Paola Cinnella, Giuseppe Pascazio
Summary: A high-order shock-capturing central finite-difference scheme is evaluated for numerical simulations of hyper-sonic high-enthalpy flows out of thermochemical equilibrium. The scheme utilizes a tenth-order accurate central-difference approximation of inviscid fluxes, along with high-order artificial dissipation and shock-capturing terms. The proposed approach demonstrates accuracy and robustness for a variety of thermochemical non-equilibrium configurations.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Philipp Bahavar, Claus Wagner
Summary: Condensation is an important aspect in flow applications, and simulating the gas phase and tracking the deposition rates of condensate droplets can capture the effects of surface droplets on the flow while reducing computational costs.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Andras Szabo, Gyorgy Paal
Summary: This paper introduces an efficient calculation method, the parabolized stability equations (PSE), for solving stability equations. By calculating LU factorization once in each marching step, the time spent on solving linear systems of equations can be significantly reduced. Numerical experiments demonstrate the effectiveness of this method in reducing the solution time for linear equations, and its applicability to similar problems.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
A. Khalifa, M. Breuer
Summary: This study evaluates a recently developed data-driven model for collision-induced agglomerate breakup in high mass loading flows. The model uses artificial neural networks to predict the post-collision behavior of agglomerates, reducing computational costs compared to coupled CFD-DEM simulations.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Chunmei Du, Maojun Li
Summary: This paper considers the bilayer shallow water wave equations in one-dimensional space and presents an invariant domain preserving DG method to avoid Kelvin-Helmholtz instability.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Jean-Michel Tucny, Mihir Durve, Andrea Montessori, Sauro Succi
Summary: The prediction of non-equilibrium transport phenomena in disordered media is a challenging problem for conventional numerical methods. Physics-informed neural networks (PINNs) show potential for solving this inverse problem. In this study, PINNs were used to successfully predict the velocity field of rarefied gas flow, and AdamW was found to be the best optimizer.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Min Gao, Pascal Mossier, Claus-Dieter Munz
Summary: In recent decades, the arbitrary Lagrangian-Eulerian (ALE) approach has gained popularity in dealing with fluid flows with moving boundaries. This paper presents a novel algorithm that combines the ALE finite volume (FV) and ALE discontinuous Galerkin (DG) methods into a stable and efficient hybrid approach. The main challenge of this mixed ALE FV and ALE DG method is reducing the inconsistency between the two discretizations. The proposed algorithm is implemented into a loosely-coupled fluid-structure interaction (FSI) framework and is demonstrated through various benchmark test cases and complex scenarios.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Dawid Strzelczyk, Maciej Matyka
Summary: In this study, the numerical convergence of the Meshless Lattice Boltzmann Method (MLBM) is investigated through three benchmark tests. The results are compared to the standard Lattice Boltzmann Method (LBM) and the analytical solution of the Navier-Stokes equation. It is found that MLBM outperforms LBM in terms of error value for the same number of nodes discretizing the domain.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Kanishka Bhattacharya, Tapan Jana, Amit Shaw, L. S. Ramachandra, Vishal Mehra
Summary: In this work, an adaptive algorithm is developed to address the issue of tensile instability in Smoothed Particle Hydrodynamics (SPH) by adjusting the shape of the kernel function to satisfy stability conditions. The effectiveness of the algorithm is demonstrated through dispersion analysis and fluid dynamics simulations.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Luis Laguarda, Stefan Hickel
Summary: We propose several enhancements to improve the accuracy and performance of the digital filter turbulent inflow generation technique, such as introducing a more realistic correlation function and varying target length scales. Additionally, we suggest generating inflow data in parallel at a prescribed time interval to improve computational performance. Based on the results of large-eddy simulations, these enhancements have shown to be beneficial. Suppressing streamwise velocity fluctuations at the inflow leads to the fastest relaxation of pressure fluctuations. However, this approach increases the adaptation length, which can be shortened by artificially increasing the wall-normal Reynolds stresses.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Constantin Zenz, Michele Buttazzoni, Tobias Florian, Katherine Elizabeth Crespo Armijos, Rodrigo Gomez Vazquez, Gerhard Liedl, Andreas Otto
Summary: A new model for compressible multiphase flows involving sharp interfaces and phase change is presented, with a focus on the treatment of compressibility and phase change in the multiphase fluid flow model. The model's accuracy and suitability are demonstrated through comparisons with experimental observations.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Joseph O'Connor, Sylvain Laizet, Andrew Wynn, Wouter Edeling, Peter V. Coveney
Summary: This article aims to apply uncertainty quantification and sensitivity analysis to the direct numerical simulation (DNS) of low Reynolds number wall-bounded turbulent channel flow. By using a highly scalable DNS framework and UQ techniques, the study evaluates the influence of different numerical parameters on the simulation results without explicitly modifying the code. The findings provide guidance for numerical simulations of wall-bounded turbulent flows.
COMPUTERS & FLUIDS
(2024)